Bending table



R. F. ONSRUD June 4, 1940.

BENDING TABLE Filed April '7, 193a 5 SheetsSheet 1 206%, DOUGLASEOMSIPZ/D v June 4, 1940. I R. F. ONSRUD 2,203,027

, SENDING TABLE Filed April 7, 1938 5 Sheets-Sheet 2 6 7 9 6 7 Q r K 9 If 1/ 4 /3 r5 z 2; 2/ Z2 78 I6 Z0 22 21 f7 79 Z4 a z: 6 2/ 9 m E f5 I? zI 20 4 /7 9 Z4 Z3 22 5 ZZ fl67ZZ/ 0 0062 06f. U/VJPUD June 4, 1940.QNSRUD 2,203,027

BENDING TABLE Filed April 7, 1938 5 Sheets-Sheet 3 .June' 4, 1940. R. F.ONSRUD BENDING TABLE Filed April 7, i938 5 Sheets-Sheet 4 001/6246OMS/BUD June 4, 1940. F. ONSRUD I 2,203,027 SENDING TABLE Filed April 7,1938 s Shee tS -Sheet 5 Patented June 4, 1940 PATENT OFFICE BENDINGTABLE Rudolph F. Onsrud, Chicago,

Onsrud Machine Works, Inc.,

corporation of Illinois 111., assignor to Chicago, 111., a

"Application April 7, 1938. Serial No. 200,597

Claims.

The construction herein disclosed is designed for furnituremanufacturers for use in making round corners. The machine is useful inbending sheet material, veneered stock, boards, laminated stock, pressedwood and similar fibrous substances responsive to the application ofheat and mechanical force for forming round corners. Relatively thickmaterial is grooved out on the inside of the ultimate curve prior tobending for the purpose of rendering the operation rapid and easy.

The objects of the invention are to provide a bending machine of theclass mentioned with improved mechanical means for rapidly performingthe bending operation with convenience and suitable for operating uponstock varying as to overall dimensions and thickness, and to provideimproved means for forcing a bend of definite radius and for maintainingthe fibrous material under compression and subject to the necessarytemperature for rapidly setting the bent material in its new form. I Theobjects of the invention are accomplished by means of a construction asillustrated in'the drawings, wherein:

Figure 1 is a fragmentary perspective view of the front side of themachine.

Fig. 2 is a perspective view of the rearside of the machine.

Fig. 3 is an edge view as bent by the machine.

Fig. 4 is a fragmentary longitudinal section through the bending andheating elements of the table.

Fig; 5 is a section similar to that shown in Fig. 4 except that thehinged portion of the table is in changed relation to the fixed portionthereof with the stock partly bent.

Fig. 6' is a view similar to Fig. 4, but with the parts in 'thatrelation when the stock is fully bent.

Fig. '7 is a sectional detail taken on the line 1--1 of Fig. 4.

Fig. 8' is a fragmentary endview of 'the table for illustrating amodification thereof employing pneumatic means for operating the hingedportion ofthe table.

Fig. 9 is a fragmentary end View repeating part of the mechanism shownin Fig. 8, but showing the hinged portion of the table swung up with thestock therein bent at right angles.

Fig. 10 is a central longitudinal section of the construction shown inFigs. 8 and 9.

Square cornered furniture is frequently objectionable on account ofpossible injury: thereof a sample of stock from. Round corneredfurniture is often favored on account of being less hazardous andbecause of its appearance. When the furniture is fabricated from fibroussheet material it is desirable to equip the factory with facilities foraccurately forming bends rapidly and in a manner to remain permanentlyin that form without stresses due to improperly set material. Thepresent bending table is designed for that purpose and is arranged sothat the bends may be 10 formed by manual operation of the machine inthe case of. light materials or by power-operated means at the option ofthe user.

The construction illustrated consists of a table I having two sets ofnormally horizontal heavy i5 guide railsZ and 3. The guide rails .2 and3 are in alignment, and each is slotted longitudinally at 4 to receiveclamping bolts 5 which carry end guides or grips 6 for receivingtherebetween the stock which is to be bent by the table. ple of materialoperated upon is indicated at 1. Exceptionally heavy stock is prepared,prior to operation thereon by the bending table, by grooving the boardas indicated at 8 and the groove A samsometimes extends down to ornear'the veneer 9.

Another preparatory step to bending is the application of a cement orglue to the surfaces of groove 8 and further the slipping into thegroove of a flexible reinforcing strip I!) for backing up the veneer.This strip is also coated with an advhesive.

The rails 2 and 3 are connected together at their inner spaced ends byabendable metal plate H such as spring bronze. The bent ends of plate IIare clamped to the rails by means of metal facings and tie elements [2for the rails. Tie elements l2 extend transversely of the rails toconnect and hold them in definite spaced relation. The rails 2 are fixedon the table while the rails 3 hinge to swing upwardly therefrom.. 40

The plate ll serves both as hinge and as pressure transmitting andbend-formingelement, or separate provision is made for the hinge asexplained for the modification shown by Figs. 8

and 9. Beneath the plate H is a pressure applying and heat transmittingblock l3. This block is preferably of an aluminum composition for rapidheat conductivity and carries an electrical heating element l4 imbeddedin the lower surface thereof. is concave,.as indicated at l5, accordingto the desired curvature of bend in material operated upon. The block isalso mounted for limited selfadjustment to accommodate the bend radiallyby the spring mounting it on supporting cast- .55

The upper surface of the block ings H, which may be in the form of armstied together by rods I8, I 9 and 2B.

The rods I8 and 20 pass through eye bolts 2| which are slidable inbearings 22 secured to the metal cross-members l2. Longitudinal motionof the eye bolts is resisted by springs 23 located between the bearings22 and nuts 24 on the ends of the bolt. By means of this mounting offorming blocks l3, a limited lateral movement of the blocks is providedfor, so that the latter may accommodate the bend in the materialoperated upon in that direction, but when the hinged part 3 is rockedupwardly, the block 13 is forced into firm contact with the bendingplate H.

An opposite pressure is applied to the material operated upon by theinward reactance thrust of the clamping member 6 against the edges ofthe stock operated upon. The cement used is resinous or of a similarnature, so that it will set and harden rapidly on the application ofheat and pressure. The heat which is applied through block l3 has theadditional function of softening the substance of the material beingbent and the bend is made easier because of the application of heat. Ifthe fibrous material contains moisture, the moisture will be convertedinto steam and aid in loosening up the fibers of the material, so thatthey may be reset in the new formation upon cooling and are not underparticular strain because of the bending operation. This is apparentfrom stock bent to round corners by this bending table, as there is notendency for the corner to bend back toward its original flat condition,nor is there a tendency for a fracture or openings occurring in thecurved surface. The finished corner may be machined, fluted, routed, orcarved.

During the bending operation the outer curved surface of the bentmaterial is supported by the metal plate I I which, toward thecompletion of the bend, is backed up by pressure received through blockl3. Plate H, therefore, serves to prevent fracture of the materialoperated upon during the bending process. The application of heat forthe proper resetting of the fibers of the board to the curvature of thebend requires from forty-five seconds to a minute and onehalfapplication through forming block or caul l3. It is unnecessary to gluea retaining veneer on the inside of the bend, also there is norequirement for close accuracy of the surface'of the inside out orgroove 8. When particularly heavy stock is operated upon and there isnecessity for more speedy penetration of heat to the bent material, anadditional heater 25, Fig. 6, is applied to the inside of the'bend.

In case of bending veneered boards, it is advisable to have the corestock grain run parallel with the bend, and then it is unnecessary tomake as deep a routed-out cut at the back of a panel as in cases wherethe core stock is run across the bend. With the grain of the woodrunning across the bend, it is preferable to rout out the back of thepanel practically to the glue line between the core and the veneer orcross-band. Where the face veneer must run across the corner, it ispreferable to run the cross-band at forty-five degrees to the grain ofthe core which may be then parallel with the corner. The thickness ofthe portion of the board which forms the bent corner depends upon theradius of the bend. In bending a thin plywood panel upon to one-halfinch thickness or heavier panels where a corner post is not necessary,the thickness possible with a one inch radius is from one-eighth tothreesixteenths of an inch; a two inch radius, onequarter inchthickness; a three inch radius, three-eighths to one-half inch inthickness.

The machine is useful with a wide range of' or casein glues or theconventional animal or vegetable glues and no means provided forclamping or removing the material in bent form, it is necessary to allowthe material to remain in the machine from one to several minutes.

The hinged portion of the table is lifted by hand when lightweightmaterial is operated upon, and is retained at the required angle to theremaining portion ofthe table by the hooks 26, Fig. l, drawn tight byeccentric latch elements 21.

Figs. 8 and 9 illustrate a modification wherein. apneumatically-operated plunger 30 in a cylinder 3! is employed forforceably swinging the hinged portion of the table. In these views thehinged portion is indicated by numeral 32, and the stationary part ofthe table by numeral 33. The two parts of the table are hinged togetherby a flexible bend-forming plate 42 which is the same as thebend-forming plate ll of Figures 1, 2, 4 and 5 and serves the samefunction. The two parts of the table are also connected together inhinged relation by the support for the pressure-applying and heatingblock 4!. (See Figs. 4 and 5 where the block is numbered l3.) Motion istransmitted to the hinged part of the table from plunger 30 through thelinkage 34. The fixed part 33 of the table carries brackets 35 to whichare hinged at 36 brackets 31 slidably engaging portion 32 of the table.Bracket 35 carries adjustable stops 38 for engagement with pads 39 onbrackets 31. The stock operated upon is indicated in Figs. 8 and 9 as aboard 40. The pressure applying and heating block 4| is mountedsimilarly to block l3 shown in Figs. 4 and 5, and its function is thesame; that is, providing a concave support of definite radius forreceiving the bent corner and holding it to form while it becomes set inthat condition through the'application of heat and pressure.

In the operation of the bending table the heating element iscontrolledas to temperature and period of application ofheat. Suchcontrol means, however, is not detailed in the drawings, as theinvention relates to the construction of the bending table. Inperformingthe'bending operation, the stock operated upon is placed between thecleats 6 when the hinged'part 3 of'the table is horizontal in alignmentwith the stationary part 2, as shown'in Fig. 4. The hinged part 3 isthen lifted to swing around or to whatever angle of bend is required.The plate ll connecting the parts 2 and 3 forms the hinge and flexes toa curvature of a predetermined radius corresponding to the concavesurface of heating block l3. The material operated upon presses downagainst the plate as the bend is being formed. The cleats 6 form endabutments for the board operated upon and force the bending area thereofagainst plate II.. The heating caul or block l3 applies oppositepressure to plate II with full contact along the concave surface of theblock when the bend is fully formed. The block supports l1 hinge on thetie rods l8 and 20 and the eye bolt supports 2| for the tie rods mayshift in their bearings against the spring 23 as these bearings moveapart upon swinging motion of the moving part of the table withreference to the stationary part.

This spring mounting of the supports for the block, together with thesprings l6 which permit a limited motion of the block around tie rod l9,provide for any needed self-adjustment of the block to the bend in thematerial operated upon. When using a machine such as illustrated inFigs. 1 and 2,.the hinged part of the table is held at the requiredangle with the stationary part of the table, during application of heatand pressure to permanently set the material in bent form, by means ofhooks 26 and eccentric latches 21. In the form of machine illustrated byFigs. 8 and 9, thehinged part 32 of the table is held in its movedposition the required length of time by the hydraulic or pneumaticoperating means shown in these figures.

The forming operation provides an economical way of making a permanentcorner construction for furniture. The joint is strong withoutreinforcements and while these are used for extra strength, nothing needbe glued on the inside of the bend, as it will hold its shape. Theapplication of heat and pressure allows the material to re-set in itsnew form free of stress. Ordinary ungrooved three-ply material of athickness commonly required in furniture is readily bent without injurydue to the protection aiforded by the forming element I3.

I claim:

l. A bending table of the class described, provided with a two-partsupport for fiat material, one part of which support is free to hingerelatively to the other part of the support, a hinge connection betweenthe two parts of the support consisting of a flexible metal plate,a'heat and pressure applying block having a concave surface for engagingsaid plate, and a mounting for said block extending between thestationary and hinged portions of the bending table arranged to pressthe block against the plate according to the angular position of thehinged portion of the support with reference to the stationary portionof the support.

2. A bending table of the class described, provided with a two-partsupport for flat material,

one part of which support is free to hinge relatively to the other partof the support, a hinge 50 connection between the two parts of thesupport consisting of a flexible metal plate, a heat and pressureapplying block having a concave surface for engaging said plate, and aresilient mounting for said block extending between the stationary andhinged portions of the bending table arranged to press the block againstthe plate according to the angular position of the hinged portion of thesupport with reference to the stationary portion of the support.

3. A bending table of the class described, provided with a two-partsupport for flat material, one part of which support is free to hingerelatively to the other part of the support, a hinge connection betweenthe two parts of the support consisting of a flexible metal plate, aheat and pressure applying block having a' concave surface for engagingsaid plate, and a resilient slid- I able mounting for self-adjustment ofsaid block extending between the stationary and hinged portions of thebending table arranged to press the block against the plate according tothe angular position of the hinged portion of the support with referenceto the stationary portion of the support.

4. A bending table of the class described, comprising a pair ofangularly adjustable worksupporting elements for the material operatedupon, a pivot hinge connection for said elements, power-operated meansfor effecting angular motion between said supporting elements, aflexible metallic plate forming an additional hinge connection betweensaid supporting elements and forming therebetween a continuation of thesupport, a pressure and heating block resiliently and slidably supportedon said hinged elements and having a curved surface for engagement withthe flexible plate upon relative angular motion between the supportingelements.

5. A bending table of the class described, provided with a two-partsupport for material operated upon, one part of which support is free tohinge relatively to the other part of the support, a hinge connectionbetween the two parts of the support consisting of a flexible metalplate, a pressure block, and a resilient mounting for said blockextending between the two parts of the support arranged to press theblock toward the plate according to the angular relation between the twoparts of the support.

RUDOLPH F. ONSRUD.

CERTIFTCATE OFTCYIYRECTION.

Patent No."2,205,027. June L 1911.0.

RUDOLPH F. ONSRUD.

It is hereby certified that error appears in, the above numbered patentrequiring correction as follows: In the drawings, Sheets 1 to )4inclusive, signature of inventor, for "Douglas P. Onsrud" read-RudolphF. Onsrud-; and that the said Letters Patent should be read withthis correction therein that the same'may conform to the record of thecase in the Patent Office.

Signed and sealed this 6th day of August, A. D. l9LLO.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents;

